The present invention relates generally to battery recharging systems, and more particularly to an improved contactless battery recharging system, such as may be used in electric vehicles and the like to enhance safety, reliability and user convenience.
Given the anticipated proliferation of electric vehicles, it will be necessary to have a distributed and reasonably standardized recharging configuration, located at, for instance, the vehicle operator's residence, place of business, parking garages, recharge stations, and the like. In determining the standardized system that will be implemented on a large scale basis, the important considerations are initial cost, operating cost, reliability, and user safety.
Using currently available technology, the most likely approach for battery recharging would be a conductor metal-to-metal contact in a plug and socket arrangement supplying alternating current (AC) or direct current (DC) power to the vehicle. Charging would be accomplished by the vehicle operator physically making the connection between the vehicle and the power supply outlet. Given the high currents and voltages required to recharge electric vehicles for operation, this connection by an untrained and unskilled operator could create unnecessary hazards, particularly if no means were provided for a quick automatic disconnect of the vehicle from the charging source. Furthermore, the need for providing charging opportunities at distributed locations as mentioned above, would be impacted by these same concerns.
Other drawbacks include higher curb weight for the electric vehicle, wear and tear of high current exposed contacts, as well as the safety issues, particularly under fault modes and owner misuse. More importantly, the public perception of reduced safety with live high power contacts may adversely impact customer acceptance of electric vehicles. The high probability that standards and safety organizations, such as Underwriters Laboratories, may require galvanic isolation between an AC power source and the vehicle battery, raises the prospect that expensive isolated converters would be needed.
Thus, a need exists for a contactless battery recharging system, such as may be used to provide power to electric vehicles, which is directed toward overcoming, and not susceptible to, the above limitations and disadvantages.